Adding Work time interval into a SLA queue report.

Content

I currently have a report looking at the Service level of multiple queues completing incidents within set time frames. It currently is based of incident start and end time. But we want to adjust it to look a the time frame completed with 4, 8 12 working hours etc. 

How does this expression need to be adjusted to count on relative work time. 

Thanks, 

B

Code Snippet

             count( distinct if( inc_performance.intv_type = 13 & date_diff( inc_performance.time_end, inc_performance.time_start ) <= 14400, inc_performance.i_id ) )



count(   distinct if(                      inc_performance.intv_type = 13 &                       date_diff( inc_performance.time_end, inc_performance.time_start ) <= 86400 &